reset: Add generic reset driver

This patch adds a generic reset driver. It is designed to be useful when
one has a register in a regmap which contains bits that reset other
devices. I thought this seemed like a very generic use, so here is a
generic driver. The overall structure has been modeled on the syscon-reboot
driver.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

1 files changed, 36 insertions, 0 deletions

diff --git a/doc/device-tree-bindings/reset/syscon-reset.txt b/doc/device-tree-bindings/reset/syscon-reset.txt
new file mode 100644
index 00000000000..f136b3d2250
--- /dev/null
+++ b/doc/device-tree-bindings/reset/syscon-reset.txt
@@ -0,0 +1,36 @@
+Generic SYSCON mapped register reset driver
+
+This is a generic reset driver using syscon to map the reset register.
+The reset is generally performed with a write to the reset register
+defined by the register map pointed by syscon reference plus the offset and
+shifted by the reset specifier/
+
+To assert a reset on some device, the equivalent of the following operation is
+performed, where reset_id is the reset specifier from the device's resets
+property.
+
+	if (BIT(reset_id) & mask)
+		regmap[offset][reset_id] = assert-high;
+
+Required properties:
+- compatible: should contain "syscon-reset"
+- #reset-cells: must be 1
+- regmap: this is phandle to the register map node
+- offset: offset in the register map for the reboot register (in bytes)
+
+Optional properties:
+- mask: accept only the reset specifiers defined by the mask (32 bit)
+- assert-high: Bit to write when asserting a reset. Defaults to 1.
+
+Default will be little endian mode, 32 bit access only.
+
+Example:
+
+	reset-controller {
+		compatible = "syscon-reset";
+		#reset-cells = <1>;
+		regmap = <&sysctl>;
+		offset = <0x20>;
+		mask = <0x27FFFFFF>;
+		assert-high = <0>;
+	};